1. Field of the Invention
The present invention relates to an exhaust system and process for removing contaminant vapors from contaminated underground areas.
2. Description of the Prior Art
Various techniques are known in the art for removing large deposits of underground contaminant liquid and vapor. Such contaminants include gasoline or other normally liquid volatile petroleum products which frequently escape from underground storage tanks because of the development of leaks in the tank walls or transfer lines or because of negligent handling of these substances, e.g., because of overfilling.
A particularly efficient device for removing liquid contaminants is described in my U.S. Pat. No. 3,980,318 entitled "Underground Fluid Recovery Device" which issued Sept. 14, 1976. The device described in my patent identified above provides for large scale recovery of liquid and vaporized underground contaminants (e.g., gasoline) from subterranean areas contaminated therewith and may be employed to remove substantially all of such contaminant liquid and vapor. However, use of the device described in my patent is relatively expensive in terms of manpower expended and equipment cost. The device therefore must be moved from location to location for optimum efficient commercial use, once substantially all liquid contaminant has been removed from the contaminated area, although small amounts of residual contaminant vapor may still remain. To remove this residual contaminant vapor from the underground contaminated area would require a considerably longer period of time for my large-scale recovery device to remain in continued use on a particular location and the amount of vapor that could be removed does not economically justify such long-term usage. Accordingly, there exists a need for a simpler, less expensive exhaust system that may be used as an auxiliary to my largescale recovery device for use at a location over a considerable period of time to remove substantially all traces of residual contaminant vapors from contaminated underground areas.